The present invention relates to copying machines or like image forming apparatus for forming copy images, for example, on paper precut to a specified size and a roll paper cutting device for use with the apparatus.
As the means for feeding copy paper to the image forming position, image forming apparatus, such as copying machines, generally have incorporated therein a cassette for containing paper precut to a specified size and delivering the cut paper therefrom one sheet after another. Alternatively, sheets of such cut paper are manually inserted one by one into a copy paper inlet formed in the body of the apparatus.
However, the apparatus for use with such cut paper has the drawback of necessitating a large space for holding the paper therein when the paper to be used has a large size. Accordingly, paper in the form of a roll is usually set in a specific roll paper cutting device, cut to the desired size by the device and then fed to the image forming apparatus through a paper inlet.
This method is cumbersome and inefficient because the roll paper must be cut by the device before an image forming operation. The drawback can be overcome by incorporating a roll paper cutting mechanism into the image forming apparatus, such that when a roll paper mode is selected as the paper feed mode for the apparatus, cut paper is fed from the cutting mechanism. In this case, however, an image forming apparatus having a special and complex construction must be newly fabricated at an increased cost. Furthermore, the user possessing an apparatus not incorporating the cutting mechanism must purchase the new apparatus.
Conventional roll paper cutting devices are adapted to cut roll paper to a predetermined size but are unable to cut the roll paper in conformity with the size of documents fed to the image forming apparatus. Accordingly, the conventional device requires the cumbersome procedure of measuring the size of documents first and feeding the measurement to the cutting device as the desired cutting size.
Further in the case where the image forming apparatus is adapted to be equipped with the roll paper cutting device as an optional device, with signal communication effected to associate the device with the apparatus, the modification of the apparatus and wiring require much labor to impair the optionality. When the roll paper cutting device is to be used as such an optional device, the roll paper feed means within the device and the paper feed means within the apparatus must be adapted to transport paper at the same speed, whereas this encounters extreme difficulty. If there is a difference between the two feed means in transport speed, the roll paper is likely to become deflected or tensioned to produce an adverse effect on the formation of images especially when elongated documents are copied. Further when the two speeds are to be made identical, the drive source for the roll paper feed means, for example, must be finely adjusted, but the means for effecting the fine adjustment is expensive, consequently diminishing the advantage of the image forming apparatus.